<script?type="text/javascript">

	function?hasClass(?obj,?cls?){?
	????return?obj.className.match(new?RegExp("(\\s|^)"?+?cls?+?"(\\s|$)"));
	}
	
	function?removeClass(?obj,?cls?){?
	????if(?hasClass(?obj,?cls?)){?
		????//remove
			var?reg?=?new?RegExp("(\\s|^)"?+?cls?+?"(\\s|$)");
			obj.className?=?obj.className.replace(reg,?"");
		}
	}
???
????//定義getByClassName函數(shù)，讓函數(shù)實(shí)現(xiàn)給對(duì)象增加class?
????function?addClass(obj,?cls){
????????if(!hasClass(obj,?cls)){
????????????obj.className?+=?"?"?+?cls;
????????}
????}

	function?getByClassName(obj?,?cls){
		var?elements?=?document.getElementsByTagName('*');
		var?result?=?[];
		for?(var?i?=?0;?i?<?elements.length;?i++)?{
			if?(elements[i].className?==?cls)?{
				result.push(elements[i]);
			};
		};
	}

	window.onload?=?function(){
		window.onscroll?=?function(){
			var?top?=?document.documentElement???document.documentElement.scrollTop?:?document.body.scrollTop;
			?/*兼容IE瀏覽器*/
			var?menu?=?document.getElementById('menu').document.getElementsByTagName('a');

			var?items?=?getByClassName(document.getElementById('content'),'item');

			var?currentId?=?"";

			for?(var?i?=?0;?i?<?items.length;?i++)?{
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				var?_itemTop?=?_item.offsetTop;
				if?(?top?>?_itemTop?-200)?{
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				}else{
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					var?_menu?=?menu[j];
					var?_href?=?_menu.herf.split("#");

					if?(_href[_href.length?-?1]?!=?currentId)?{
						removeClass(_menu,"current");
					}else{
						addClass(_menu,"current");
					};
				}
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		}
	}
	</script>